1. Field of the Invention
The present invention relates to a mediate server and real time delivery method between different networks, and particularly, to an improved mediate server and real time delivery method between different networks which are capable of providing a real time video service between different networks having a different network speed by installing a mediate server in a proxy server of a high speed local network or a fire wall.
2. Description of the Conventional Art
There are problems in providing a video information in real time on the Internet. In particular, since the video information requires a fast response time and a wider bandwidth, it is impossible to provide a service in real time. The video service is performed on a conventional low speed Internet network as follows:
A first method is performed by using a guaranteed bandwidth. Namely, this method is directed to reserve a bandwidth and protocol that a video data requires. This method is very useful for installing a network and protocol for a Video On Demand (VOD). However, this method has a problem in that the protocol must be installed in a server and a router, etc. for using the same on the Internet.
A second method is generally used for a conventional Internet service, which downloads all video data into a user memory space and displays a video signal based on the user's system. This method is very easy to implement since the real time processing on the network is not required. However, there are problems in that the user must wait until the downloading is finished, and in the case of a larger video data, there are time delay and memory space limit.
A third method is directed to displaying the video when the receiving video data exceeds a predetermined amount by using a stream protocol. This method uses a self-defined low speed encoding method and a protocol. However, this method has a problem in that it is impossible to guarantee a desired bandwidth for processing data in real time since there is an intermediate node on the Internet.
A fourth method is directed to using an adaptive protocol, which was adapted to a system such as the Vosaic in Illinois university. This method is directed to browsing a data by a user, and preventing a data transfer delay based on a result of the browsing. The result of the browsing is transferred to the server for controlling the transfer speed of the server. In addition, this method is intended for providing the service without changing the conventional router system on the Internet. However, a related protocol and method must be supported by the server.
As described above, it is impossible to provide a better video service without increasing the speed of the network between the user and the server. It is possible to provide the video service in real time since a desired speed is obtained in the high speed local network; however, since it is impossible to install servers related to all video services in the high speed network, the Internet on which it is possible to obtain much information is used. In this case, the proxy server may be used by caching a serviced video data; however, the method is limitative in accordance with the capability of the system and a size of the video data.